iodine vapor for glycogen screen

SLForsburg susan_forsburg at qm.salk.edu
Fri Oct 27 12:58:07 EST 1995

"N. Kent Peters" <kent at ibg.uit.no> wrote:
>I wish to screen bacterial colonies on a petri plate for glycogen 
>synthesis.  I have a refernece that used a "iodine vapor" method.  

I dont know if there is a special trick for your system, but we 
routinely stain  the yeast S. pombe with  iodine vapour
 to identify asci (the spore walls contain starch).  We purchase 
flaked solid iodine, put a thin layer of flakes in an empty
 petri dish,  and place the plate with the colonies upside down
over the iodine dish.  Wait ten minutes, and hey, presto, the
asci stain dark.  You can speed it up by heating the plate with 
the iodine but that  isnt necessary.

We keep the iodine dishes in a tightly sealed container in the hood
and all the manipulations are done in the hood.  THe cells are killed
by the vapor and the colour is transient;  continued sublimation
will take all the stain away within a few hours. 

hope this helps.

S L Forsburg                             
susan_forsburg at qm.salk.edu        
 "I don't speak for the Institute,         
 and the Institute doesnt speak for me."

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